Furnace.



J. W. HAYS.

FURNACE. APPLICATION FILED JAN. 5, 1906. RENEWED NOV.l, 1909.

Patented May 3, 1.910.

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' J. W. HAYS.

FURNACE.

APPLIOATION'IILED JAN; 5, 1906. RENEWED 11011, 1909.

Patented May 3, 1910.

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FURNACE. APPLIUATION rum) JAN. a, 1906. RENEWED NOV.1, 1 909.

957,158. Patented May 3, 19 10.

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unis srna us: airnn'r orieien JOSEPH W. HAYS, OF CHICAGO, ILLINOIS, ASSIGNOR TO CARE-OX COMPANY, A CORPORATION OF ILLINOIS.

FURNACE.

names.

Specification of Letters Patent.

Patented May 3, 1919.

Original application filed April 28, 1904, Serial No. 205,297. Divided and this application filed January 5, 1906, Serial No. 294,793. Renewed November 1, 1909. Serial No. 525,810.

To all whom it may concern:

Be it known that I, JOSEPH 1V. Hays, a citizen of the United States, residing at Chicago, Cook county, Illinois, have invented new and useful Improvements in Furnaces, of which the following is a specification.

This application is a division of my application Serial No. 205,297, filed April 28, 1904.

The purposes of my invention are to provide improved means for controlling the admission of air into furnaces so as to insure the thorough combustion of all combustible matter in the fuel, and especially to provide improved means for admitting a predetermined maximum supply of the air and to cause a gradual decrease in the supply of air from such maximum to a certain prede termined minimum quantity during a certain interval of time after each firing, and in connection with the latter purpose to provide improved timing apparatus for automatically changing the air between certain limits during a certain predetermined interval of time.

It consists of the features of construction set forth in the claims, and shown in the actual drawings, in which,

Figure 1. is a longitudinal section of a furnace and showing my invention applied to an ordinary horizontal fire-tube boiler. Fig. 2. is a front elevation of the same. Fig. 3. is an enlarged front elevation, partly broken away, of the system of dampers for controlling the supply of air to the furnace, shown in Fig. 1. Fig. 4. is a side elevation of the same. Fig. 5. is an elevation partly sectional of the automatic timing device for regulating the dampers. Fig. 6. is an enlarged detail plan view of the connection between the door and gate-valve in the'waste pipe for opening and closing the same. Fig. 7. is an enlarged axial section of the valve operated by the furnace door for controlling the supply of water.

The boiler, 1, is constructed in the usual manner mounted upon lugs resting on the masonry of the boiler setting. The space below the boiler is separated by the bridge wall, 2, into a fire-box, 3, and combustion chamber, 4, communicating with each other through the passage, 5. The grates, 6, form the bottom of the firebox and separate the same from the ash-pit 7. Fuel is fed to the furnace through the fire-doors, 8, in the boiler-front, 9. A hollow arch 10 interlocking with the brick wall above the fire-doors at the forward end of the grates is provided with a central air-passage, 11, communicating through a plurality of inlets, 12, with the fire-box. Above the bridge-wall, 2, at the rear end of the grates is a second arch, 13, which is also provided with a central longitudinal air-passage 14, having air-inlets, 15, extending through the front wall of the arch and adapted to discharge air in a forward direction over the grates.

The air-passages, 11, and 14 in the arches, 10, and, 13, communicate respectively with the air conduits, 18 and 19 which extend rearwardly along the sides of the inner walls or upon the floor of the combustion chamber, 4, and upwardly at the rear of the combus tion chamber to a point above the boiler setting, so that air taken into the conduits, 18, and 19 will be drawn from the hottest part of the boiler room.

The flow of air through the conduits, 18 and 19 is in each case controlled by two dampers. The upper .dampers, 20, are rigidly secured in certain positions of adjustment by means of the thumb nuts, 21, and control the maximum volume of air delivered through the conduits. The second set of dampers, 22, are pivotally mounted in the damper boxes, 23, which form part of the conduits, 18 and 19 and are provided with doors, 24, on the front side to permit of access to same for the purpose of adjusting the dampers, 22. Both of the dampers, 22, are rigidly secured to the damper rod, 25, which is journaled in one corner of the damper-boxes and has rigidly secured thereto outside of the boxes a disk, 27, to which is hung a counter-weight, 28, which normally urges the dampers into an open position. Each of the dampers, 22 has an opening 29 which is adapted to permit a certain predetermined amount of air to pass through the conduit when the damper is in its closed po sition. The area of the opening, 29 is in each case adjusted by means of a slide, 30. The dampers operate simultaneously but are separately adjustable.

For each boiler, there is rigidly mounted upon the boiler front a vertical cylinder, 31 having a piston 32. With the lower end of the cylinder, 31 there is connected a pipe, 33 supplied with water underpressure through a pipe, from a main, 35 controlled by a valve 36. Intermediate the valve 36 and the connection of the pipe, 34 with the pipe, 33 there is a valve, 37 having a downwardly protruding stem, 38 overhanging a cam, 39 on the upper end of the pintle of the hinge of the fuel door, 8 the cam being sloped to operate against the valve stem, 38 for opening the valve when the fuel door is opened and the valve being closed automatically as by a spring, 37 when the cam is rotated by the closing of the fuel door away from position at which it forces the valve open. The pipe, 33 below the connec tion therewith of the supply pipe, 3-1 extends to any proper waste connection, and intermediate the junction of the pipe, 34 and such waste connection is a needle valve, 41 which may be set to restrict the outflow to the waste to any desired extent, and thereby to govern the time occupied in emptying the cylinder, 31 when the supply of water to said cylinder is cut off. The stem, 32* of the piston, 32 operates the cord or cable, 43 which extends to and over the sheave or disk, 27 and said piston stem carries the 'damperclosing weight, 28 and the cord carries also a counter-weight, 28 at tached to it at the opposite side of the sheave. The weight, 28 is enough heavier than the weight, 28 to operate the damper, 22 and move the piston, 32 downward in the cylinder, 31 when the water pressure is withdrawn from below the piston. The operation of these connections, it will be seen, is that when the fuel door is opened for firing, the valve, 37 will be opened, admitting water to the pipes, 34 and 33 and cylinder, 34 under the pistons, 32 lifting the latter and opening the valve, 22 admitting air to the fire-box to the maximum amount permitted by the adjustment of the valve, 21. When the fuel door is closed, the closing of the valve, 37 shuts off the water supply and. the water will waste from the piston, 31 past the needle valve, 41 at a rate determined by the adjustment of that valve, thus causing a gradual closing of the damper, 22 occupying for complete closing the amount of time ascertained by experience to be sufiicient for the burning off of the more combustible or volatile portions of the fresh fuel, and reducing the latter to condition requiring for further combustion the minimum air supply provided by the aperture in the damper, 22. The adjustment of the valve, 41 will be made by the operator in accordance with the customary amount of fuel supplied at each charge, and in view of the character of the fuel, as ascertained by experience therewith.

Under certain conditions in respect to character of fuel and work requirements, it may be useful to provide for closing the dampers, 22 immediately upon closing the fuel door after firing, or, at least, abruptly instead of gradually, after proper interval. In order to permit such operation of the structure, a by-pass, 45 is provided, connecting the pipe, 33 above the valve, 41 with said pipe below said valve, and in this by-pass there is provided a gate-valve, 42. This gate-valve will be closed in all cases in which the valve, 41 is designed to operate for gradual closing of the damper, 22 but for abrupt closing of said valve, or for more rapid closing than would result from the adjustment of the valve, 41, the gate-valve, 42 may be opened more or less. If opened widely, the by-pass pipe 45 Will permit immediate evacuation of the cylinder, 31 and cause abrupt closing of the damper, 22. From the fuel door, 8 a link, 43 may be connected with the stem of the gate-valve, 42 so that the opening of the door will close the valve and the closing of the door will open the valve. The connection between the door and the link may be adjustable so as to vary the extent to which the-valve is opened by the closing of the door. A convenient mode of adjustment is that shown in which a lever arm 44 extending from the door to receive the pivotal connection of the link, is slotted so that the pivot-pin, 46 may be set at varying distances from the hingepivot of the door, and thereby made to give the valve a longer or shorter stroke upon the movement of the door from open to closed position, the wide-open position of the door in all cases closing the valve. hen it is not desired to have the door operate this valve automatically the fireman will disconnect the link by lifting it off the pivotpin, 46. The valve, 42 will then be left closed and the regulation will be effected by the needle-valve, 41 as described. It Wlll be obvious that the valve, 42 may be operated entirely at will, if desired, and serve as a means for abruptly causing the closing of the dampers, 22 in any instance in which it may appear desirable to do so.

The air, which is discharged from the apertures, 15 in the arch, 13 flows in a forward direction in opposition to the flow of gases in the fire-box and becomes thoroughly mixed with such gases, and also assists in causing air entering through the arch, 10 to be mixed with said gases. These gases, together with the air, pass through the intensely heated area of the passage 5 where complete combustion takes place. The walls of the conduits, 1S and 19 are heated through contact with the gases in the combustion chamber, and the walls of the passages through the arches are heated by flames in the firebox, so that the temperature of the air in conduits is increased considerably before its delivery into the firebox.

In order that complete combustion of all combustible matter in the fuel shall take place and that smoke shall be prevented, it is essential that sufficient air shall be supplied to the furnace to furnish the necessary quantity of oxygen for such complete combustion; but in order that the efficiency of the boiler shall not be reduced by the cooling of the gases due to an excessive admixture of air, it is necessary that the admission of air be under perfect control and that it vary in quantity; that is, that a maximum quancity of air, just sufficient to suit the needs of the furnace immediately after firing, be admitted at that time, and that such quantity be gradually reduced to correspond with the rate at which volatile matters are being given off by the fuel until the amount of air has reached a certain minimum quantity which corresponds exactly to that required for the consumption of the colorless gases or oxids arising from the unison of the oxygen passing up through the grates with the fixed carbon or coke upon the grate. Since these maximum and minimum quantities of air required by the furnace are different for different furnaces and difierent fuels, the value of the adjustments, which will be hereinafter described will be readily understood.

To adjust the dampers, 20 for the maximum volume of air admission, the dampers are first closed and all air excluded. This will cause the generation and emission of smoke. The time during which smoke is discharged is then carefully noted, which gives us the period required for the coking of the coal and other data necessary for the adjustment of the automatic device regulating the reducing dampers, 22. The dampers, 20 are now gradually opened and are finally permanently fixed by the thumb nuts at the point where just enough air is admitted to eliminate all smoke after a fresh firing of coal. The maximum volume of air necessary is thus determined and provided for.

The next adjustment is that of the mechanism for gradually reducing the amount of air admitted above the grates from the maximum quantity, which is required immediately after firing, to the minimum quantity, which is required after the fuel has all been brought to an incandescent state and all of the volatile parts of the fuel have been burned. Since the dampers, have already been set for the maximum quantity, the remaining adjustment consists of setting the device for timing the closing of the dampers, 22. This timing is accomplished by setting the needle valve, 41 in the pipe, 38 as above described. This valve is so set that the piston in the cylinder, 31 will, after having been raised to its highest position by the opening of the valve, 37 descend to its lowest position in the interval of time required for reducing to incandescence the quantity of fresh fuel that is thrown upon the fires at each operation of firing. This interval of time has already been determined by experiments in connection with the dampers, 20.

There now remains only the adjustment of the slides in the dampers, 22. These are set to admit a certain minimum amount of air from the conduits when the dampers, 22 are closed. This minimum quantity of air is the amount that is needed to effect combustion of the gas 00, given off by the incandescent coke. This is determined by adjusting the slides, 30, until a maximum temperature is found in the combustion chamber at such times between firings when all of the fuel on the grates is in an incandescent state. The temperature of the combustion chamber may be measured by means of a pyrometer.

The mechanism which is herein shown offers practically no resistance to the opening of the fire doors. lVhen one of the doors, 8 is opened and fresh fuel is thrown upon the fire, the dampers, 22 are automatically opened and the maximum quantity of air is delivered through the arches, 10 and 13. This quantity is gradually reduced through the closing of the damper, 22 controlled by the cylinder, 31 until, after the interval of time required for reducing such fresh coal to incandescence, the admission of air will have been reduced to its minimum quantity at which it will remain until the next firing of the furnace makes an increase in the quantity of air again necessary and causes a repetition of the operation.

It will be noted that separate means of furnishing and regulating the air supply are provided for each arch. It will be found in many cases that greater efficiency can be attained by increasing or diminishing the supply of air admitted to one or the other of these arches. My arrangement of the dampers, 20 and 22 in connection with the individual conduits to each arch makes such separate regulations possible where desired.

I claim,

1. In a furnace, in combination with the combustion chamber, a conduit for supplying air thereto; a damper in such conduit for regulating the air supply; a cylinder and piston therein, the cylinder having water supply and waste connections, the piston being operatively connected with the damper for opening and closing the latter; a valve which controls the water supply and operative connections from the fuel door to such valve for opening and closing the valve when the door is opened and closed; a valve in the waste connection, and operating connections from the fuel door for closing it when the door is opened and open ing it when the door is closed.

2. In a furnace, in combination with the combustion chamber, a conduit for supplying air thereto; a damper for controlling the air supply through such conduit, a cylinder and a piston therein, the cylinder having water supply and waste connections, the piston being operatively connected with the damper for opening and closing the latter; a valve in the waste connection adjustable at will to regulate the rate of waste; a by-pass pipe leading around such valve; a second valve in the bypass pipe, and means for opening and closing such second valve.

3. In a furnace, in combination with the combustion chamber, a conduit for supplying air thereto; a damper for controlling the air supply through such conduit; a cylinder and a piston therein, the cylinder having water supply and waste connections, the piston being operatively connected with the damper for opening and closing the latter; a valve in the waste connection adjustable at will to regulate the rate of waste; a bypass pipe leading around such valve; a second valve in the by-pass pipe, and connections thereto from the fuel door for closing the valve when the door opens and opening it when the door closes.

4;. In a furnace, the combination of a grate; a firebox above said grate; an airinlet for discharging air into said fire-box above the grate; adjustable means for controlling the maximum amount of air delivered by said air-inlet; a damper operated independently of said means and adapted to control the passage of air through said air-inlet, said damper having an aperture through the same for determining the minimum quantity of air passing through said inlet; a slide for adjusting the area of the opening through said damper; means controlled by the movement of opening of the door of the furnace for opening said damper, and a timing device adapted to automatically close said damper in a predetermined interval of time after the opening of same.

In witness whereof, I have hereunto signed my name this 15th day of May A. D., 1905 in the presence of two subscribing witnesses.

JOSEPH W. HAYS. lVit-nesses:

FREDK. Gr. FISCHER, R. B. HOLLEY. 

